1. Field of the Invention
The invention relates to an inspection method for a secondary battery and, in particular, to an inspection method for a secondary battery in which quality is determined by performing aging treatment.
2. Description of Related Art
As a related secondary battery, a secondary battery that includes an electrode body in which a positive electrode and a negative electrode are stacked via a separator has been known. In the case where a foreign material such as a metal is mixed in a portion between the positive electrode and the negative electrode during manufacturing of such a secondary battery, the positive electrode and the negative electrode are possibly short-circuited, which possibly causes short-circuit failure by which a battery voltage is significantly lowered.
As an inspection method for the related secondary battery that detects such short-circuit failure, a method described in Japanese Patent Application Publication No. 2009-004389 (JP 2009-004389 A) has been known, for example. It is described in JP 2009-004389 that, in the inspection method for the secondary battery that includes a process of performing first aging treatment under a high-temperature environment and a process of performing second aging treatment under a lower-temperature environment than the first aging treatment, a terminal voltage V1 of the secondary battery before performance of the second aging treatment is measured, a terminal voltage V2 of the secondary battery after the performance of the second aging treatment is measured, and failure caused by a short circuit of the secondary battery is determined from a voltage difference ΔV between the terminal voltage V1 and the terminal voltage V2.